Feudalism refers to the political and military system that developed in
Western Europe during the Middle Ages. Although it provided no
strong central government, it served basic needs for order and
protection.

The foundation upon which feudalism was based was the ownership and
power over land. In the A.D. 400s, after Germanic tribes had
conquered the West Roman Empire, the land was divided into many small
realms or kingdoms, over which different tribes and clans had
power. In the absence of the central and regional Roman
governments, tribesmen were loyal only to their families and
chiefs. Thus began the dark ages, a time during which invasions
and small wars were constantly breaking out across Europe.

Feudalism developed to meet the needs of the time. It was becoming
common practice for the owner (person in power over) of a particular
realm to grant portions of his land to others in return for goods and/or
services. However, the expansion of the Muslim Empire into Spain
by the 700s threatened all of Western Europe. So many turned
ownership of their land over to a powerful lord in return for
protection. These people then still stayed on the land as tenants,
ultimately becoming the peasants or "serfs" of the manorial
system (see manorialism). The lord provided the protection by
granting portions of his land to warriors who swore allegiance.

In this practice, the owner eventually came to be known as the
lord. The person giving goods and services in return (the lords
subject) was the vassal, while the land he received was called the fief.
As development of the system progressed, some standards developed.
When the lord granted the vassal his fief, the vassal then had to hire
knights, the number depending on on the size of the fief (which ranged
anywhere from a plot of land to an entire territory). In hiring
knights, the vassals then took the role of the lord, granting land for
service. The same then may have been done with the knights hired
by the vassal. It was in this way that the hierarchical nature of
feudalism developed, all based on the defense of the land. As we
will see, the primary defensive factor was represented by the castle,
which commanded the land. If the castle was held, then the land
was held. And if the castle fell to a siege, then the land was
lost to the enemy.